The present invention relates to a method of testing light-emitting condition of a vacuum fluorescent print head. The invention relates more particularly to a method of testing light-emitting condition of a vacuum florescent print head of a type having a plurality of luminous elements disposed along a main scanning direction for forming dots in the form of a linear column on a print paper. For forming a planar image, i.e. an image having both a width and a length, from a plurality of linear dot columns juxtaposed with each other, the print head is movable in a sub-scanning direction relative to the print paper.